Olefin reactions



Patented Aug. 16, 1949 OLEFIN REACTIONS John 1:. Roland and JesseHarmon, Wilmington, DeL, minors to. E. L du Pont de Nemonrs & Company,Wilmington, DeL, a corporation of Delaware No Drawing. Application April21, 1944, Serial No. 532,219

9 Claims. (01- 260413) This invention relates to oleflne reactions, andparticularly to a process for reacting oleflnes, such as ethylene, withcarboxylic acid anhydrides. It also relates to new compositions whichmay be prepared by reaction between ethylene and carboxylic acidanhydrides. The type of reaction with which this invention is concernedis essentially a polymerization of the olefin in the presence of areactant, one molecule of which supplies both end groups for the longchain or modified polymeric molecule. For convenience, such a reactionmay be referred to as "telomerization and the modifiedpolymeric productsas telomers.

In the copendin application of W. E. Hanford and J. R. Roland, S. N.471,028, filed January 1, 1943, now U. S. Patent 2,402,137, it isdisclosed that ethylene undergoes a telomerization reaction withnumerous saturated organic. oxygen-containing materials, includingcarboxylic acid anhydrides, in the presence of certain catalysts whichare considered to be effective as sources of free radicals, namelyperoxides, persulfates, oxygen, perborates, percarbonates, hydrazines,tetraethyl lead, hexachloroethane and the like. While the proceduredescribed in the Hanford and Roland application is widely applicable inthe preparation of novel reaction products of ethylene withoxygen-containing organic compounds, the process described in theabove-mentioned application gives relatively low yields when applied tothe reaction of ethylene with certain carboxylic acid anhydrides.

An object of the present invention is to provide an improved process forreacting ethylene with carboxylic acid anhydrides. Another object is toprovide new and superior catalysts for the reaction of ethylene withcarboxylic acid anhydrides. Yet another object is to provide newcompositions of matter which may be prepared by the reaction of ethylenewith carboxylic acid anhydrides.

These and other objects are accomplished in accordance with thisinvention by heating ethylene with a carboxylic acid anhydride in thepresence of a catalyst, particularly a catalyst containing a positivehalogen. A reaction takes place in accordance with this inventionwhereby the ethylene molecules combine in the form of a linear chain, towhich the terminal groups are supplied by the carboxylic acid anhydridereactant. The resulting product is a carboxylic anhydride of relativelyhigh molecular weight. In one of its simplest forms, the invention maybe illustrated by the following equation, in which the 2 anhydridereactant, for purposes of illustration, is propionic anhydride n=aninteger having a value of from approximately 2 to 100) arsimultaneouslyproduced. Under certain conditions, as hereinafterdescribed, at least a minor part of the product may be obtained in theform of carboxylic acid rather than anhydride. In particular, thecarboxylic acids, rather than the anhydrides may be produced ifconditions are such that secondary reactions, such as hydrolysis, mayoccur.

The reaction of ethylene with a carboxylic anhydride is generallyconducted, according to this invention, at a temperature of 100 to 400(3., preferably 150 to 350 C. Super-atmospheric pressures, e. g., 100 to1500 atmospheres, are em-- ployed, preferably 400 to 1000 atmospheres,the upper limits of operable pressures being determined solely by thestrength of available equipment.

The catalysts which are most effective in the practice 01 this inventionare the positive halogen compounds. By positive halogen compounds" ismeant any compound which yields an alkali hypohalite when treated withan alkali hydroxide. These compounds include: inorganic hypochloritessuch as calcium hypochlorite; alkali metal- N-haloaryl sulfonamides,such as potassio-N- chloroparatoluene sulfonamide, sodioN-chloroparatoluene sulfonamide, sodio N-chlorobenzene sulfonamide;N-haloamides, such as 1,3-dichloro- 5,5-dimethylhydantoin, N-chlorourea,l-chloro- 5,5-dialky1hydantoins, 3-chloro-4,4-dialkylhydantoins;N-haloalkane sulfonamides and organic hypochlorites such as tertiarybutyl hypochlorite. It is significant that these catalysts are noteffective in the conventional Friedel-Crafts or alkylation types ofreaction, which, of course, are quite unlike the present invention.

The amount of catalyst which is used in the performance of thisinvention is between 0.0001

3 and 5.0% of the total weight of reactants. The preferred range isabout 0.001% to 1.0% of the weight of the reactants.

The ethylene which is employed as a reactant may contain smallquantities of ethane, propane, nitrogen, hydrogen, carbon dioxide oroxygen. Oxygen in high concentrations, for example in excess of 1000 P.P. M., is generally deleterious to the reaction. Small amounts ofoxygen, however, less than 1000 P. P. M., and preferably less than 50 P.P. M. do not have a marked effect on yield, and only a minor eflect onthe molecular weight of the products produced. While ethylene givesoutstanding results in this telomerization reaction, other oleflns,particularly those lower oleiins or mixtures of oleflns which polymerizein the presence of oxygen or peroxides, also may be used.

The reaction is best effected by reacting ethylene with carboxylic acidanhydrides having from 3 to 16 carbon atoms and at least one hydrogenattached to the carbon atom adjacent to the carboxylicanhydride group.

In carrying out this telomerization of ethylene and acid anhydrides ingeneral, the anhydride, ethylene, and catalyst are charged into apressure-resistant vessel, preferably after purging the reaction vesselof air with deoxygenated nitrogen or other inert gas and withthecharging operation carried out under a blanket of inert .gas. Thevessel is closed, connected with a heating apparatus and a reservoir ofethylene. After the selected temperature has been reached the course ofthe reaction may be followed by the ethylene pressure drop. The desiredpressure of ethylene in the agitated vessel is usually maintained byintermittent injection of ethylene.

Though it is generally not desirable, the anhydride may be diluted withan inert solvent, or with 'a solvent which is less reactive towardsethylene than the anhydride. If desired additional amounts of anhydrideor inert solvent may also be injected after the reaction has started.

When the reaction is finished, as may be noted by the cessation ofethylene absorption, the reaction vessel is cooled, bled of excessethylene, opened, and the reaction mixture is removed. The wax-likeproduct may be isolated by any convenient process, such as bydistillation of the" volatile components of the reaction mixture atordinary or low pressures. The product contains long chain fatty acidanhydrides, and may contain small amounts of the long chain fatty acidswhich may sometimes be produced during the condensation reaction,particularly if small amounts of water are present. The long chain acidsmay also be obtained from the reaction product by any conventionalmethod employed for obtaining organic acids from anhydrides. Thus thecrude mixtures may be subjected to the action of steam, whereby theproduct is recovered largely in the form of fatty acids rather thananhydrides. Alternatively, the crude mixture can be esterified, and thevarious esters so formed can be separated by .fractional distillation.The corresponding acids may be prepared readily by saponifying theesters and acidifying the saponiflcation products. The inventionembraces the products produced by means of the telomerization reaction,particularly the higher fatty acids and their anhydrides. The inventionis illustrated further by the following examples.

Example I.A silver-lined high pressure reactor of 400 cc. capacity ischarged with 200 grams of propionic anhydride and 0.3 gram of 4 sodioN-chlorotoluene sulfonamide. The vessel is closed, evacuated, and placedin a, shaker machine, wherein it is heated at a temperature of 198? to203 C., while the contents are subjected to the action of ethylene at apressure of 640 to 840 atmospheres, for a period of 14.25 hours. Afterremoval from the reactor the reaction mixture is placed in a still, andthe unreacted propionic anhydride is recovered by distillation. Thecombined product of four such runs weighs 236 grams, and is a telomer ofethylene and propionic anhydride. It has a saponification number of228.4 and an acid number of 57.2.

- Example -II.A silver-lined high-pressure reactor of 400 cc. capacityis charged with 200 grams of propionic anhydride and 0.3 gram of sodioN-chlorotoluene sulfonamide. The vessel is closed, evacuated and placedin a shaker machine, wherein it is heated at a temperature of 197 to 207(3., while the contents are subjected to the action of ethylene at apressure of 760 to 970 atmospheres for a period of 12.5 hours. Afterremoval from the reactor the crude reaction product is diluted with 300grams of water and 300 grams of alcohol, and the resulting mixture isheated in a still on a steam bath until the water, ethyl propionate, andexcess alcohol are removed. The residue is a soft pasty mass which iscompletely soluble in dilute aqueous sodium hydroxide. The alkalinesolution forms a strong stable foam on agitation, and wets sulfurreadily. On analysis, the pasty mixture is found to have an acid numberof 161.1, corresponding to a molecular weight of 346, a saponificationnumber of 146, a molecular weight (ebulliscopic method) of 382, and aniodine number of 1.2. A mixture of fatty acids is readily obtained fromthe solution in alkali by the addition of dilute mineral acid.

Emmple III.A crude reaction product obtained in several runs bytelomerization of ethylene and propionic anhydride as described inExample II is esterified by means of ethyl alcohol in the presence ofp-toluene sulfonic acid catalyst. and with benzene as an agent forazeotropic removal of water. When the esteriflcation is complete, theresidue is poured into cold saturated potassium carbonate solution,separated from the water, washed until neutral and dried. Distillationof this yields 165 parts of ethyl propionate and 224 parts of higherboiling material. The

. latter fraction is then distilled at 1 mm. on a steam bath, yieldingparts of condensate. Precision distillation of the condensate gives 10parts of material boiling at 83 to 84 C. at 38 mm., identified byanalysis (68.89% carbon, 11.39% hydrogen and a saponiflcation number of157) and determination of physical properties (density of 0.817,refractive index at 25 C. of 1.4109, and conversion of the ester by wayof its chloride to an anilide melting at 91-92 C. and a p-anisidemelting at 102" C.) as ethyl alpha-methylhexanoate (cf. C. A. 26, 2701;29, 115). The distillation residue is subjected to moleculardistillation at a pressure of 10 microns. Thirteen separate cuts aremade, the overall boiling range being to 350 C. The cuts havesaponiflcation numbers which range from 327.2 in the lowest boiling to10.7 in the highest boiling. This indicates molecular weights of 172 to5250. The following table 75 shows the properties of the variousfractions,

- which correspond to ethyl esters of acids of the has a value ofapproximately 21. In the fractions.

boiling above 300 'C. n has a'value higher than about 21, the major partof this high-boilina product corresponding to the esters derived fromanhydrides oracids in which the value of Ms within the range of 21 to100. I i Y Ethyl esters of ethylene-propionic anhydride telomer:

. MoiIWt. Y Distillation Wt.0ut Percent Sap. out empt.,0 grams of TotalNo fig oo 5.2 4.2 1.21.2 "112 100 11.3 13.8 333.2 me no 120 a 11 281.8200 m 150 13.1 10.15 2111.0 210 150 110 as 1.1 211.1 ass 110 195 12810.2 1am so: no 205 as 4.6 165.6 7 sec 205 220 1.1 22 163.1- e44 220 25016.2 13.0 140.11 an 250 210 11.5 9.2 111.2 416 210 300 as 1.0 12.1 101300 s30 a1 4.1; 27.8 2,020 330 350 3.0 2.4 10.1 5,250

. The isolation of these esters, together with the identification ofethyl alpha-methylhexanoate (an ester of H(CH2CH2)2CH(CH3)COOH),provides evidence as to the jnature of the anhydrides 6 ene-propionioanhydride telomers tends to increase with increased telomerizationpressures.

Example V.A mixture containing 200 parts 01' isobutyric anhydride and0.3 part of audio N- chloro-p-toluene sulfonamide is processed withethylene at 193 to 201 C. under 790 to 970 atmospheres pressure for 16.7hours. There is obtained 238 parts of a reaction mixture from which I '1the excess isobutyric anhydride is evaporated to give an isobutyricanhydride-ethylene telomer. Analysis of the telomer by alcoholysis andhydrolysis shows it to be a mixed anhydride of isobutyric acid and anacid having an average molecular weight of 341. There is obtained byhydrolysis 85 parts of. an acid having an acid number of 197.7corresponding to an average molecular weight of 284, and an iodinenumberof 4.9.

Thus the telomer is a long chain fatty acid anhydride, having an averageof nearly 10 ethylene units in the (CH:CH2),|H chains which areattachedto the alpha carbon atoms.

Example TIL-Example II is repeated except for the substitution ofvarious anhydrides, as shown in the table below, for propionicanhydride.In each case, 200 parts by weight of the anhydride are employed- Theproducts are waxy compositions which 'upon hydrolysis give I long chainalkali-soluble acids. When acetic anand acids produced byjthetelomerization reaction showing that the telomers are the result ofintroducing a chain comprising a plurality of directly combined ethyleneunits attached between an alpha carbon and a hydrogen of the carboxylicanhydride. Thus the anhydrides produced in Example II are for the mostpart compounds of the formula H(CH2CH2)1ZC(CH3)COOCOCH2CH3 wherein n hasa value M3 to approximately 100.

The saponification products of these esters can be acidified to yieldthe corresponding fatty acids.

Thus the acids derived from the saponification products of cuts 1 and 2include H(CH2CH2) aCH (CH3) COOH.

and the acid H(CH2CH 4CH(CH:1)COOH is correspondingly obtained from out4. The acids derived from cuts 10 to 13 inclusive may be represented bythe formula in which n is an integer having an average value of 13 orhigher.

Example IV.--Example II is repeated, except 4 for the choice of reactionpressure. The effects of reaction pressure on the productare-illustrated in the following table. The average number of carbonatoms present in the acids obtained by hydrolysis of the telomers isdetermined by titration. v

Yi id 1 fi r b e s o r 0 a1- 11 338??? es Acids, Atoms in the p r gramsAcids (by titration) (l) 780 $0 980 29 33 2) 600 to 700 25 I 360 to 50023 17 The above analyses clearly show that the average length of thepolyethylene chain in the ethylhydride isused. the reaction mixtureyields a hard, waxy composition.

Example VIL-A mixture containing grams of isobutyric anhydride and 0.3gram of calcium Initial Weight Yield of Molecular Propionic Ratio ofMixed Weight Anhydride, Propionic Acid, (from Acid.

grams Anhydrlde:- grams No.)

Ethylene These experiments show that the'molecular weight of the telomeris' higher when the ratio of carboxylic anhydride to ethylene in thecharge is decreased.

The data contained in the above examples illustrate the novel reactionof this invention, whereby ethylene and carboxylic acid anhydrides yieldlong chain fatty acid anhydrides,.particularly when reacted in thepresence of a com.- pound containing a. positive halogen atom. Thereaction is not limited to the anhydrides used in the examples, but isapplicable generally to alkanoic anhydrides which have at least onehydrogen on a carbon alpha to a carboxylic anhydride group. Theseinclude such mixed anhydrides as acetic-propionic, acetic-isobutyric,

benzoic-propionic, pivalic-propionic, pivalic- 1sobutyric, and the like,as well as cyclic alkandioic anhydrides, such as alpha-methyisuccinic,alphamethoxysuccinic, glutaric, alpha-methylglutaric; alpha-,alpha-dimethylglutaric; beta, beta-dimethlglutaric. In the examples, theweight ratio of carboxylic acid anhydride to ethylene varies from 1:3 to1:0.14. Actually the operable range is much wider, including 1:10 to1:003. In a continuous apparatus the wider range of relativeconcentrations is more readily employed than in batchwise operation.

As stated above, diluents are generally not necessary in thetelomerization of ethylene with acid anhydrides' according to theinvention. Relatively inert diluents which may be used include tertiarybutyl methyl ether, methyl pivalate, toluene, benzene and chlorobenzene. High- 1y branched sterically hindered compounds, like isoootane,pentamethylethane, pivaloin, pivalone,

. and the like may be used as reaction media even though some containsecondary or tertiary hydrogens.

The products may be separated into their individual components in themanner described in Example III or by fractional crystallization orprecipitation from solution.

The products of this invention find wide application for practical uses.The primary products,

which are anhydrides, can be used to make fabrics water repellent. Theseanhydrides can also be converted to esters which are valuable as waxes,softeners, plasticizers, and special lubricants. The acids or anhydridesare readily converted to synthetic soaps by reaction with alkali.

Organic solutions of these soaps may be used as dry cleaning agents.Alkaline earth and heavy metal soaps may be used as bodying agents forwaxes and greases. Certain heavy metal and substituted ammonium soapsshow value as protective coatings against corrosion. These syntheticlong-chain acids find use as milling aids in the processing of naturaland synthetic rubbers and as an anti-tack agent for calendaringplastics. The primary anhydride products may be readily converteddirectly or indirectly to amides. These derivatives find use in wax andpolish compositions. The amides may befurther reacted with an aldehyde,for example formaldehyde, to yield N-methylolamides which find use inthe water repellent finishing of paper and fabric. The methylolamidesmay be further reacted with a salt of a tertiary amine or an ammoniumsalt to yield high grade permanent water repellent finishes. Theanhydride mixtures obtained by this process maybe converted by knownreactions to long-chain alcohols, sulfates,

chlorides, mercaptans and nitriles. The uses to which such secondaryproducts may be put are generally well known to the art.

We claim:

1. A process for preparing long chain fatty acid anhydrides whichcomprises reacting ethylene with a carboxylic acid anhydride having atleast one hydrogen atom on a carbon alpha to the carboxylic anhydridegroup under superatmospheric pressure at a temperature in the range 100to 400 C. in the presence of a positive halogen compound which yieldsalkali hypohalite when treated with an alkali hydroxide.

2. A process for preparing long chain fatty acid anhydrides whichcomprises reacting ethylene with a carboxylic acid anhydride having atleast one hydrogen atom on a carbon alpha to the car- 8 boxylicanhydride group under a pressure of 400 to 1000 atmospheres, at atemperature in the range of 100 to 400 C. in the presence of a positivehalogen compound which yields alkali hypohalite when treated with analkali hydroxide.

3. The process set forth in claim 2 in which the said positive halogencompound is an alkali metal N-haloaryl' sulfonamide.

4. The process set forth in claim 2 in which the said carboxylic acidanhydride is propionic anhydride and the said positive halogen compoundis sodio N-chlorotoluenesulfonamide. j

5. The process set forth in claim 2 wherein the said carboxylic acidanhydride contains from 3 to 16 carbon atoms per molecule, and at leastone hydrogen atom attached to a carbon atom adjacent to the carboxylicanhydride group.

6. In a process for preparing long chain fatty acid anhydrides, thesteps which comprise reacting ethylene with a carboxylic acid anhydridecontaining 3 to 16 carbon atoms per molecule and at least one hydrogenatom attached to a carbon I atom adjacent to the carboxylicacid'anhydrlde at a temperature in the range of 150 to 400 C. and at apressure in the range of 400 to 1000 atmospheres in the presence of apositive halogen compound which yields alkali hypohalite when treatedwith an alkali hydroxide, and thereafter separating from the resultingreaction product a mixture of long chain fatty acid anhydrides.

' 7. The process set forth in claim 6, wherein the said carboxylic acidanhydride is isobutyric anhydride.

8. In a process for preparing long chain fatty acid anhydrides, thesteps which comprise heating one part by weight of carboxylic acidanhydride with 0.03 to 10 parts by weight of ethylene and from 0.0001%to 5.0% of a positive halogen compound based on the weight of ethyleneplus anhydride, at a temperature in the range of to 400 C. undersuperatmospheric pressure, and separating from the resultant reactionmixture the product containing compounds of the class of long chainfatty acid anhydrides.

9. In a process for preparing long chain fatty acid anhydrides the stepswhich comprise heating one part by weight of propionic anhydride with0.14 to 3 parts by weight of ethylene and from 0.001% to 1.0% of analkali metal N-haloaryl sulfonamide based on the weight of ethylene plusanhydride, at a temperature in the range of to 400 C. under 400 to 1000atmospheres pressure, and separating from the resultant reaction mixturethe product containing compounds of the class of long chain fatty acidanhydrides.

JOHN R. ROLAND. JESSE HARMON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS OTHER REFERENCES Beilstein, 4th edition, vol. 11,pages 323 and 324. Beilstein, vol. II, Vierte Auflage Literature of1920-29.

